Process of effecting solidification of fluid nitrate of lime.



. SOHARFF.

LIDIFIOATION 0F FLUID NIT APPLICATION FILED JULY 3, 1912.

RATE OF LIME.

Patented Oct. 6, 19M.

arm

UNITED STATES PA I HYDRO-ELEKTRISK KVAELSTOFAKTIESELSKAIB. 0F QHRTSTIANIA,

nonwar.

rzaocnss or nrrno'rme SOLIDIFICATIQN or FLUID nrrna'rn or LIME.

Specification of Letters Patent. Application filed July 3, 1812. Serial No. 707,598.

Patented @ct. 6, 191-1.

To all whom it may concern:

Be it known that I, MAX ScHAnFF, a subject of the Emperor of Germany, residing at Ludwigshafen-on-the-Rhlne, have invented certain new and useful Improvements in Processes of Eifecting Solidification of Fluid Nitrate of Lime; and 31 do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the,

accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

This invention has for its object a process of effecting the solidification of fluid nitrate of lime.

It has been found that fluid nitrate of lime, such as for instance obtained by evaporation of nitrate of lime solutions, only solidifies very slowly. The reason for this lies toa great extent in the viscous nature of the mass and the considerable amount of heat set free by the solidification,

In the process now in use the nitrate of lime solution is caused to flow, into flat iron pans in which it requires several days to be completely solidified. 'The cutting out and the crushing of the pieces necessitates a great deal of manual work and the further grinding in ball mills requires a considerable power consumption.

To promote the cooling of the viscous mass it is useful to spread it in thin layers over cooling surfaces, but even then a ratherlong time and consequently a large cooling surface is required the solidification itself of the cold mass only proceeding very slowly.

To enable cooled surfaces, onto which the mass is applied in thin layers and from which it is continually scraped off, to be ad; vantageously employed, it is in the first place necessary that the solidification should take place rather quickly, and secondly that the product that has been scraped off, shall not again stick or adhere together, but admit of being ground in suitable apparatus.

According to the present invention this is obtained by applying the massonto a cooled surface provided with a scraper, after it has been S11b180l38d to an energetic'cooling process and has thereby been brought into the form of a mixture of solidified 71. 6. crystallized and non-solidified particleS. This op- Germany,

eration on the one hand produces a quantity of crystals, which, in the subsequent solidification act as centers of crystallization for initiating or completing the solidification of the remainder of the mass; and, on the other hand, removes to a great extent the cap-ability of the mass of rising to too hi h a temperature due to the heat of crystallization. When such a pasty mass is distributed in'a thin layer, for instance on a rotating cooled roll, it will be solidified during the rotation of the roll, so that on being scraped off, it will fall ofi\in more or less scale-like pieces which willwnot again adhere together. By using this method it is possible to quite considerably reduce the cooling surface and quicken the solidification. It is convenient to proceed in the following manner, dividing the solidificationprocess into several phases and causing it to take place in a series of cooperating apparatus.

The hot mass is first cooled in any apparatus, down to, or-as it may be highly undercooled below solidification-temperature. For this purpose may be used worms or stirring coolers with water-cooling or trickle coolers. It is also very useful to employ for this purpose water-cooled rotary rolls on to which the mass is applied in a thin layer and from which it is scraped off after being cooled.

The cooled viscous mass is caused to flow into a vessel Which is slightly cooled and in which the solidification process is initiated, if desired by adding nitrate of lime powder, and is continued until there is obtained an intimate, still liquid mixture of solid and liquid particles. To enable this to take place as quickly as possible, the mass has to be stirred or kept in motion. This paste is transferred, in a thin layer, on to a cooling surface on which it is completely solidified. This hardening process takes place so quickl that, as already mentioned, it may be e fected with great advantage on a cooled surface provided with a scraper, for instance in a flat pan with water or air-cooled bottom across Which in suitable intervals a scraper is passed. A rotary cooled roll with a scraper may also suitably be employed.

hen working according to the described process much manual work is saved, and moreover the solidification is effected in the course of a few hours instead of several days. The nitrate of lime is thereby obtained in the form of thin scales the further grinding of Which only requires a slight power-consumption.

The vessel A, surrounded by a cooling" with cooled fluid jacket B, is supplied nitrate of lime through viscous mass is stirred by the mixing blades E driven by a shaft E; after a short time the mass begins to crystallize, and said mass is then led through the valve D and the pipe F to the pan G. In this pan the cylinder H, which rotates on the hollow axle J, dips. Cooling medium is supplied to the cylinder through the hollow axle K. The solidified nitrate is scraped oil the cylinder by means of the scraper or knife L.

Claims- 1. Process for effecting the solidification of fluid nitrate of lime, Which comprises the steps of cooling the fluid While stirring the same until a viscous mass is obtained conthe tube C. The

amazes taining crystals of nitrate of lime, then forming a thin layer of this viscous mass on a cooled surface to complete the crystallization and solidification and scraping the thin hardened product from said surface.

2. The process of efi'ecting the rapid soliciification of fluid nitrate of lime, Which comprises sets in, thereby forming crystals that subsequently act as centers of crystallization and also reduce the total heat of crystallization, then forming the mass into a thin layer on a cooling surface to complete the crystallization and solidification, and scraping the thin, hardened product from said surface.

In testimony that I claim the foregoing as my invention, I have signed my name in presence of two subscribing Witnesses.

MAX SCHARFF.

Witnesses:

J. Arno. LLOYD, S. H. SHANK.

cooling the mass until crystallization 

